/**
 * Copyright (c) 2012-2016, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.jspengine.compiler;

import org.tinygroup.jspengine.JasperException;

import javax.servlet.jsp.tagext.TagVariableInfo;
import javax.servlet.jsp.tagext.VariableInfo;
import java.util.Hashtable;
import java.util.Vector;

/**
 * Class responsible for determining the scripting variables that every
 * custom action needs to declare.
 *
 * @author Jan Luehe
 */
class ScriptingVariabler {

    private static final Integer MAX_SCOPE = Integer.valueOf(Integer.MAX_VALUE);

    public static void set(Node.Nodes page, ErrorDispatcher err)
            throws JasperException {
        page.visit(new CustomTagCounter());
        page.visit(new ScriptingVariableVisitor(err));
    }

    /*
     * Assigns an identifier (of type integer) to every custom tag, in order
     * to help identify, for every custom tag, the scripting variables that it
     * needs to declare.
     */
    static class CustomTagCounter extends Node.Visitor {

        private int count;
        private Node.CustomTag parent;

        public void visit(Node.CustomTag n) throws JasperException {
            n.setCustomTagParent(parent);
            Node.CustomTag tmpParent = parent;
            parent = n;
            visitBody(n);
            parent = tmpParent;
            n.setNumCount(Integer.valueOf(count++));
        }
    }

    /*
     * For every custom tag, determines the scripting variables it needs to
     * declare.
     */
    static class ScriptingVariableVisitor extends Node.Visitor {

        private ErrorDispatcher err;
        private Hashtable scriptVars;

        public ScriptingVariableVisitor(ErrorDispatcher err) {
            this.err = err;
            scriptVars = new Hashtable();
        }

        public void visit(Node.CustomTag n) throws JasperException {
            setScriptingVars(n, VariableInfo.AT_BEGIN);
            setScriptingVars(n, VariableInfo.NESTED);
            visitBody(n);
            setScriptingVars(n, VariableInfo.AT_END);
        }

        private void setScriptingVars(Node.CustomTag n, int scope)
                throws JasperException {

            TagVariableInfo[] tagVarInfos = n.getTagVariableInfos();
            VariableInfo[] varInfos = n.getVariableInfos();
            if (tagVarInfos.length == 0 && varInfos.length == 0) {
                return;
            }

            Vector vec = new Vector();

            Integer ownRange = null;
            if (scope == VariableInfo.AT_BEGIN
                    || scope == VariableInfo.AT_END) {
                Node.CustomTag parent = n.getCustomTagParent();
                if (parent == null)
                    ownRange = MAX_SCOPE;
                else
                    ownRange = parent.getNumCount();
            } else {
                // NESTED
                ownRange = n.getNumCount();
            }

            if (varInfos.length > 0) {
                for (int i = 0; i < varInfos.length; i++) {
                    if (varInfos[i].getScope() != scope
                            || !varInfos[i].getDeclare()) {
                        continue;
                    }
                    String varName = varInfos[i].getVarName();

                    Integer currentRange = (Integer) scriptVars.get(varName);
                    if (currentRange == null
                            || ownRange.compareTo(currentRange) > 0) {
                        scriptVars.put(varName, ownRange);
                        vec.add(varInfos[i]);
                    }
                }
            } else {
                for (int i = 0; i < tagVarInfos.length; i++) {
                    if (tagVarInfos[i].getScope() != scope
                            || !tagVarInfos[i].getDeclare()) {
                        continue;
                    }
                    String varName = tagVarInfos[i].getNameGiven();
                    if (varName == null) {
                        varName = n.getTagData().getAttributeString(
                                tagVarInfos[i].getNameFromAttribute());
                        if (varName == null) {
                            err.jspError(n, "jsp.error.scripting.variable.missing_name",
                                    tagVarInfos[i].getNameFromAttribute());
                        }
                    }

                    Integer currentRange = (Integer) scriptVars.get(varName);
                    if (currentRange == null
                            || ownRange.compareTo(currentRange) > 0) {
                        scriptVars.put(varName, ownRange);
                        vec.add(tagVarInfos[i]);
                    }
                }
            }

            n.setScriptingVars(vec, scope);
        }
    }
}
